Do you have the Finnish spellchecker installed?

• https://addons.mozilla.org/en-us/firefox/addon/finnish-spellchecker/

Does it work if you set the spellchecker.dictionary pref to en-US on the about:config page?

• http://kb.mozillazine.org/about:config

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

See also:

• http://kb.mozillazine.org/Preferences_not_saved
• https://support.mozilla.org/kb/Preferences+are+not+saved

Thanks for fast reply!

Sure I have the Finnish spellchecker installed, otherwise it wouldn't work as a default :)

spellcheck.dictionary settings is set to: user set - string - en-GB, no help there...

Can't use Safe Mode to check for errors, because it disables the Finnish dictionary extension and I cannot change the dictionary then...

Everything worked fine in previous versions, the problem started with version 9.

Try to uninstall and reinstall the (British) English dictionary if that dictionary isn't working properly.

Which Firefox locale are you using?

Uninstalled all dictionaries and reinstalled, no help there. Still not able to change the dictionary from the right click menu. They appear there, but choosing them does nothing.

Try to disable all other extensions and choose the default theme if you currently use a custom theme to see if that helps.

) Still no use. I'll try uninstalling the whole Firefox and re-installing it...

Okay, I uninstalled 9.0.1 and re-installed 8.0 and everything seems to working fine. I also had problems with TinyMCE in Joomla with 9.0.1 and with this 8.0 they also seem to be working fine.

What's wrong with this 9.0.1 release?